Liberated creek no longer a source

of mercury pollution

Restoring the natural channel of a northern Michigan creek stopped the flow of mercury from underground mines into nearby Deer Lake and Lake Superior.


Partridge Creek, which flows through the city of Ishpeming in Michigan’s Upper Peninsula, was diverted from its natural course in the 1970s as a flood control measure. The creek was diverted into nearby mines, where the water picked up traces of mercury and deposited it into Carp Creek, which flows into Deer Lake. Mercury from historic mining practices contaminated sediments and fish in Deer Lake, earning the lake a spot on a list of Great Lakes Areas of Concern in 1987. The city of Ishpeming began working with state and federal agencies several years ago on a plan to divert Partridge Creek out of the mines, thereby eliminating an ongoing source of mercury entering Carp Creek and Deer Lake. Restoring the creek’s natural course — which required rebuilding parts of Ishpeming’s storm sewer system, streets and sidewalks — began in 2011. The work was completed in 2013. Moving the creek out of a manmade channel downstream of Ishpeming created new fish and habitat and increased public access to Partridge Creek. Eliminating the active source of mercury entering Deer Lake was one of the last steps in a lengthy effort to get the lake removed from the list of Great Lakes Areas of Concern. In October 2014 the U.S. EPA delisted Deer Lake—it is no longer an Area of Concern. Only three other locations around the Great Lakes have been removed from the Area of Concern list. Deer Lake joins Presque Isle Bay, Pa., Oswego River, N.Y., and White Lake, Mich. The Great Lakes Area of Concern list was originally compiled in 1987, totaling 26 sites in the United States, 12 in Canada, and 5 binational locations.

Resource Challenges Addressed

  • Mercury contamination of Deer Lake
  • Mercury contamination in Lake Superior
  • Loss of fish and wildlife habitat


Creek running through woods

Redirecting a small creek, similar to the one above, reduced mercury pollution in upper Michigan. Credit: Chagrin River Watershed Partners.

Results and Accomplishments

The project halted the flow of mercury from underground mines into Deer Lake and the southern Lake Superior watershed. It also created new habitat for trout, increased public access to the waterway and completed efforts to get Deer Lake removed from a list of Great Lakes Areas of Concern.